Perform a switchover by:
- stopping current primary node
- promoting this standby node to primary
- forcing previous primary node to follow this node
Caveats:
- repmgrd must not be running, otherwise it may
attempt a failover
(TODO: find some way of notifying repmgrd of planned
activity like this)
- currently only set up for two-node operation; any other
standbys will probably become downstream cascaded standbys
of the old primary once it's restarted
- as we're executing repmgr remotely (on the old primary),
we'll need the location of its configuration file; this
can be provided explicitly with -C/--remote-config-file,
otherwise repmgr will look in default locations on the
remote server
- this does not yet support "rewinding" stopped nodes
which will be unable to catch up with the primary
TODO:
- update help, docs
- make connection test timeouts/intervals configurable
Also refactor configuration file handling while we're at it.
Previously a configuration file would be ignored if it couldn't
be opened, however that is now treated as an error.
Related to Github #127.
- use the previously introduced repmgr_atoi() function to parse
integers better
- collate all detected errors and output as a list, rather than
failing on the first error.
If no configuration file provided, also check default Postgres
sysconfig dir.
It would also be useful to check the configuration directory
provided by the RPM/DEB packages, not sure if that's programmatically
feasible.
Ignore blank lines which consist of whitespace. Per issue #71 in
GitHub.
This fix also improves comment handling and will treat lines with
whitespace before the '#' character as whitespace.
Command to be executed each time an event is logged.
Following formatting sequences will be interpolated:
%e - event type
%d - description
%s - success (1 or 0)
%t - timestamp
No need to prefix each line with the program name; this was pretty
inconsistent anyway. The only place where log output needs to identify
the outputting program is when syslog is being used, which is done
anyway.
"pg_basebackup_options"
Enable custom options to be passed to pg_basebackup
(e.g. --max-rate, --checkpoint, --xlogdir)
"tablespace_mapping"
Analogue to pg_basebackup's (9.4 and later) -T/--tablespace-mapping
option.
Tablespace mapping could also be passed via "pg_basebackup_options",
however by providing a separate parameter it makes the configuration
file easier to read and allows us to verify the specified tablespaces
exist (pg_basebackup won't do this, which can lead to undesired
behaviour, i.e. attempting to create the tablespace in the original
path).
Previously, the pg_bindir parameter was mandatory and could only be
provided in the repmgr.conf file, which was leading to the slightly
bizarre situation that e.g. for "clone standby", repmgr was complaining
that it didn't want the configuration file when it actually did.
pg_bindir is now optional - if not provided, it will use the default
path. It can be provided in the repmgr.conf file, or as a command
line parameter; the latter overrides the former.
Previous behaviour was somewhat counterintuitive, with an error
message being logged if no configuration file provided or found,
even though this is not actually an error.
Configuration files now handled like this:
- if a configuration file is explicitly provided (-f), error out
if not found.
- if no configuration file explicitly provided, attempt to open
default configuration file; if this does not exist, log
notice and continue with default values.
Also, for 9.4 and later add a hint about replication slot usage
if 'use_replication_slots' not set.
